Background The incidence of shoulder injuries in overhead sports is high. Despite this high rate, insufficient evidence is available on the efficacy of preventive training programs.

Objective To analyze the absolute and relative outcomes of shoulder injury prevention programs in non-injured overhead athletes.

Design Systematic literature review.

Setting Amateur and professional.

Participants Athletes of different throwing sports.

Interventions We analyzed different prevention approaches in injury prevention programs, based on neuromuscular components, proprioceptive training, strength, plyometric exercises or other specific prophylaxis exercises. The following electronic databases were searched: MEDLINE, PubMed, PEDro. This systematic review was registered in PROSPERO data (PROSPERO 2013: CRD42013005769). Detailed search strategy is available from http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42013005769. Articles quality was assessed according to the 11-item Physiotherapy Evidence-Based Database (PEDro) Scale.

Main outcome measurements Primary: absolute parameters of the effectiveness of injury prevention programs, such as the reduction of shoulder injury rate during the analyzed period of time. Secondary: relative outcomes such as improvement in biomechanical factors (e.g. throwing velocity, isokinetic strength) as a result of the applied injury prevention and/or performance enhancement programs.

Results Our searches identified 827 potentially relevant articles. By reviewing titles and abstracts, we identified 26 articles examining the efficacy of shoulder injury prevention programs in overhead athletes. There were no paper reporting absolute outcomes. As the relative outcomes authors most frequently used: shoulder strength, power, throwing velocity, range of motion.

Conclusions Conflicting evidence has been found. Not all of the PEDro criteria could be satisfied, as the experimental crossover design implemented by the majority of studies resulted in subject and therapist blinding not being possible. High-quality studies investigating the shoulder injury prevention are needed to reduce the incidence of injuries in non-injured overhead athletes.